<p><span style="font-size: small;"> How do you keep increasing performance in a power constrained environment like a smartphone without decreasing battery life? You can design more efficient microarchitectures, but at some point you&rsquo;ll run out of steam there. You can transition to newer, more power efficient process technologies but even then progress is very difficult to come by. In the past you could rely on either one of these options to deliver lower power consumption, but these days you have to rely on both - and even then it&rsquo;s potentially not enough. Heterogeneous multiprocessing is another option available - put a bunch of high performance cores alongside some low performance but low power cores and switch between them as necessary.</span></p> <p class="p1"><span style="font-size: small;"> <span class="s1">NVIDIA recently revealed it was doing something similar to this with its upcoming Tegra 3 (Kal-El) SoC. NVIDIA outfitted its next-generation SoC with five CPU cores, although only a maximum of four are visible to the OS. If you&rsquo;re running light tasks (background checking for email, SMS/MMS, twitter updates while your phone is locked) then a single low power Cortex A9 core services those needs while the higher performance A9s remain power gated. Request more of the OS (e.g. unlock your phone and load a webpage) and the low power A9 goes to sleep and the 4 high performance cores wake up.&nbsp;</span></span></p> <p class="p1"><span style="font-size: small;"> While NVIDIA&rsquo;s solution uses identical cores simply built using different transistors (LP vs. G), the premise doesn&rsquo;t change if you move to physically different cores. For NVIDIA, ARM didn&rsquo;t really have a suitable low power core thus it settled on a lower power Cortex A9. Today, ARM is expanding the Cortex family to include a low power core that can either be used by itself or as an ISA-compatible companion core in Cortex A15 based SoCs. It&rsquo;s called the ARM Cortex A7.</span></p> <p class="p1"><span style="font-size: small;"><a target="_blank" href="http://www.anandtech.com/show/4991/arms-cortex-a7-bringing-cheaper-dualcore-more-power-efficient-highend-devices">Read more...</a><br /> </span></p>